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The nickel-metal hydride batteries for its high-power, high-capacity, small memory effect, safety performance is good, cheap, green pollution, etc. have a broad space for development. But for the battery positive electrode material spherical nickel hydroxide has been the existence of the problem of high activity and high density can not be both. The nickel-metal hydride batteries at home and abroad, and pointed out the existing problems of the nickel metal hydride batteries. Control chemical crystallization in homemade battery cathode material in the preparation of a continuous stirred tank reactor (CSTR) spherical nickel hydroxide. Use of the material thermodynamic theory, scanning electron microscopy (SEM), X-ray diffraction (XRD), electrochemical performance tests and research tools in-depth study of pH, reaction time, the concentration of nickel ions and ammonia nickel than spherical nickel hydroxide materials the influence of the surface morphology, crystal structure, bulk density, and electrochemical properties. Thermodynamics of Materials, theoretical calculations show that, when the pH of the reaction control in between 9.5-11.5 nickel hydroxide in ammonia aqueous alkali system thermodynamics dynamic balance, to achieve complete precipitation, can effectively avoid excessive nickel ions in the system or lye generate colloidal . SEM analysis showed that the nickel hydroxide prepared are spherical particles, the particle size of coarse, uniform distribution of the particle diameter from a few microns to 20 microns. XRD analysis showed that the polymorph are a β-Ni (OH) 2, a unit cell structural integrity, the orderly crystal structure. Similarly increased first reaction pH value is the impact of spherical nickel hydroxide structure and performance of the main factors in a certain range, with the increase of the pH value, the spherical hydroxide nickel bulk density first increases and then decreases, particle size distribution large and then decrease the pH value is too large system over saturation, poor crystallinity easy to form colloidal morphology sheet, grain refinement therefore reduce the bulk density. The pH value at between 10.5-11.5 have a higher bulk density, particle size distribution, good sphericity. The reaction time conducive to crystallization. With the extension of reaction time hydroxide nickel particles gradually increases in size from the the loosely structured fine corporation fluff, into particles of a larger size the reunion shaped spherical, eventually become a dense structure of spherical particles, the particle size is evenly distributed in the 2 -18μm. The nickel ion concentration is too large too small difference of the material of the spherical, low bulk density, so the concentration of the nickel ion is a suitable control in the 0.1-0.12mol / L. Bulk density first increases and then decreases as the ammonia nickel ratio increases, the high density of the electrode material of ammonia nickel than easy to get between 1-1.2. The constant current charge-discharge test shows that the particle size increased discharge capacity decreased bulk density increased discharge capacity decreases. pH 10.5-11.5, the nickel ion concentration of 0.1-to 0.12mol / L ammonia nickel ratio of 1-1.2, and the reaction time gt; 24 hours, the preparation of nickel hydroxide having a high discharge capacity and a stable discharge platform. Therefore, when the pH of 11, the concentration of the nickel ion to 0.12mol / L ammonia nickel ratio is 1.2, the reaction time of ≥ 24h, the preparation of spherical hydroxide good sphericity of nickel particles, good fluidity, while having a good discharge capacity and high bulk density, is ideal for high-performance battery cathode material.
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